Scientists discover new blood-vessel-generating cells

Researchers from the University of Helsinki, Finland are learning to isolate and efficiently produce these stem cells found in blood vessel walls which could lead to treatment of various diseases.

The growth of new blood vessels, also known as angiogenesis, is needed in adults when repairing damaged tissue or organs.

Unfortunately, malignant tumours are also capable of growing new blood vessels to receive oxygen and nutrients. In other words, the treatment of diseases would benefit from two types of methods: ones that help launch the process of angiogenesis and ones that make it possible to prevent the process.

Medications that prevent the growth of new blood vessels have already been introduced, but their effectiveness and long-term efficacy leave much to be desired.

For a long time, it was assumed that new cells in the blood vessel walls of an adult originate in the bone marrow.

In an article published in the Proceedings of the National Academy of Sciences (PNAS) in 2008, Professor Petri Salven's research team showed that such stem cells were not found in bone marrow.

In his new research Salven has located exactly where these mysterious stem cells originate.

"We succeeded in isolating endothelial cells with a high rate of division in the blood vessel walls of mice. We found these same cells in human blood vessels and blood vessels growing in malignant tumours in humans," Salven said.

"These cells are known as vascular endothelial stem cells, abbreviated as VESC. In a cell culture, one such cell is able to produce tens of millions of new blood vessel wall cells," Salven said in a statement.

"Our study shows that these important stem cells can be found as single cells among ordinary endothelial cells in blood vessel walls. When the process of angiogenesis is launched, these cells begin to produce new blood vessel wall cells," Salven added.

The effects of new endothelial stem cells when tested in mice showed that the growth of new blood vessels weakens and the growth of malignant tumours slows if the amount of these cells in the organism is below normal.

Correspondingly, a high number of new blood vessels quickly emerge where new stem cells are implanted.

"The identification and isolation of an entirely new adult stem cell type is a significant discovery in stem cell biology. Endothelial stem cells in blood vessels are particularly interesting, because they offer great potential for applications in practical medicine and the treatment of patients," said Salven.

The study was published in the journal PLOS Biology.